1. Field of the Invention
This invention relates to a storage system and an additional storage apparatus connecting method for the storage system, and is suitable for use, for example, for making settings to connect an additional storage apparatus to a storage system.
2. Description of Related Art
According to the SAS (Serial Attached SCSI) connection standards, each units in the hardware is obliged to have its own WWN (World Wide Name), i.e., unique identification information. Accordingly, basic storage apparatuses and additional storage apparatuses that are to be SAS-connected to each other having the same SAS-ID cannot be connected. Because of this, when attempting to connect storage apparatuses having the same SAS-ID, it has been necessary to provide each storage apparatus with a SAS-ID changing function piece of hardware, such as a rotary switch, so that connection between storage apparatuses with the same SAS-ID can be avoided. In other words, settings have been made manually to avoid the overlap of SAS-IDs for storage apparatuses connected to the same network.
The technique described below has been known as an address-setting system for a 1-N serial communication system. In this technique, each slave unit receives, upon power-on, an address setting signal from a master unit and completes address setting; the switch circuit between the slave unit and the next serially-connected slave unit is closed; accordingly, the next address setting signal from the master unit can reach that next slave unit. In this way, address setting is carried out automatically in order starting with the slave unit closest to the master unit (e.g., see Patent Document 1).
Another technique described below has been known as an address setting method. In this technique, slave units in either a serial connection line or multipoint connection line are called, starting with the one closest to the master unit. For example, in the serial connection line, when a slave unit makes a response, the master unit sends an address setting signal to that slave unit so that an address is set for that slave unit. This is repeated so that addresses are set for the slave units in the serial connection in order. As a result of setting addresses for the slave units until the slave unit at the end of the serial connection line is reached, if a response is no longer made in response to the call, the slave units in the other multipoint connection line are called, starting with the one closest to the master unit, and the master unit sends an address setting signal to slave units that responded to the call and so addresses are set for those slave units. As a result of the respective slave units in either serial connection line or multipoint connection line being called in order and addresses being set for them, address setting is carried out automatically in each slave unit, even if there are branch joints (e.g., see Patent Document 2).    [Patent Document 1] JP04-223633 A    [Patent Document 2] JP08-18597 A
An in-plant test must be performed before shipping additional storage apparatuses-to-be-SAS-connected as products. Because the test requires SAS-connecting the additional storage apparatuses to each other, it is necessary to give, as SAS-IDs for use in the in-plant test, WWNs to the additional storage apparatuses.
However, the number of steps for assigning WWNs is increasingly with the number of additional storage apparatuses, so it may result in human error in manufacturing (i.e. the in-plant test).
Moreover, there are a few additional storage apparatuses that cannot be shipped as products as a result of the in-plant test. Accordingly, giving WWNs to all the additional storage apparatuses during the in-plant test consequently includes giving WWNs to those additional storage apparatuses that cannot be shipped. This is the waste of WWN setting efforts and WWN resources.
Patent Documents 1 and 2 describe automatic address setting but do not take into consideration the waste of effort in setting addresses for in-plant tests or the prevention of human errors.
This invention has been devised in consideration of the above problems and aims to provide: a storage system where, in a network regulated so that the unique identification information for a basic storage apparatus and that for each of a plurality of additional storage apparatuses do not overlap, the storage apparatuses can be connected to the network without being assigned unique identification information, effort in setting unique identification information during in-plant tests can be conserved, and human error can be prevented; and an additional storage apparatus connecting method for the storage system.